1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 *
19 */
20 package org.apache.directory.api.ldap.model.schema.parsers;
21
22
23 import java.io.Reader;
24
25 import org.apache.directory.api.ldap.model.schema.syntaxes.AntlrSchemaLexer;
26
27 import antlr.CharBuffer;
28 import antlr.LexerSharedInputState;
29
30
31 /**
32 * A reusable lexer class extended from antlr generated lexer for an LDAP
33 * schema as defined in RFC 4512. This class
34 * enables the reuse of the antlr lexer without having to recreate the it every
35 * time as stated in <a
36 * href="http://www.antlr.org:8080/pipermail/antlr-interest/2003-April/003631.html">
37 * a Antlr Interest Group mail</a> .
38 *
39 * @see <a href="http://www.faqs.org/rfcs/rfc3672.html">RFC 3672</a>
40 */
41 public class ReusableAntlrSchemaLexer extends AntlrSchemaLexer
42 {
43 private boolean savedCaseSensitive;
44
45 private boolean savedCaseSensitiveLiterals;
46
47
48 /**
49 * Creates a ReusableAntlrSchemaLexer instance.
50 *
51 * @param in
52 * the input to the lexer
53 */
54 public ReusableAntlrSchemaLexer( Reader in )
55 {
56 super( in );
57 savedCaseSensitive = getCaseSensitive();
58 savedCaseSensitiveLiterals = getCaseSensitiveLiterals();
59 }
60
61
62 /**
63 * Resets the state of an antlr lexer and initializes it with new input.
64 *
65 * @param in
66 * the input to the lexer
67 */
68 public void prepareNextInput( Reader in )
69 {
70 CharBuffer buf = new CharBuffer( in );
71 LexerSharedInputState state = new LexerSharedInputState( buf );
72 this.setInputState( state );
73
74 this.setCaseSensitive( savedCaseSensitive );
75
76 // no set method for this protected field.
77 this.caseSensitiveLiterals = savedCaseSensitiveLiterals;
78 }
79 }